System and method for improving a water heating cycle in a multi-purpose hvac system

ABSTRACT

A method for improving a water heater cycle in a system for heating water and conditioning an interior space by operating a water pump at a first rate of speed until the entering water temperature is within a desirable range, or the water pump has operated at the first rate of speed for a predetermined time, then operating the water pump at a second rate of speed.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is related to, and claims the priority benefit of, U.S. Provisional Patent Application Ser. No. 61/862,846 filed Aug. 6, 2013 the contents of which are hereby incorporated in their entirety into the present disclosure.

TECHNICAL FIELD OF THE DISCLOSED EMBODIMENTS

The presently disclosed embodiments generally relate to systems for heating water and conditioning an interior space, and more particularly, to a system and method for improving a water heater cycle in a multi-purpose heating, ventilation, and air-conditioning (HVAC) system.

BACKGROUND OF THE DISCLOSED EMBODIMENTS

A typical water heater for residential hot water production and storage is an electrical resistance water heater and storage tank, although gas water heaters are also used to heat water in a storage tank. Water heaters typically include a storage tank defining a chamber for retention of water. A water inlet pipe is provided with a first connection for interconnection with a cold water supply line that conveys fresh, relatively cold water into the storage tank. In the case of electrical resistance water heaters, there are electrical resistance elements, within the storage tank, that heat the water.

An alternative method for heating water is an active desuperheater water heater. In one example of an active desuperheater water heater, the active desuperheater water heater uses a small pump to circulate water from a water storage tank, through a heat exchanger, and back into the water storage tank. The active desuperheater water heater intercepts the superheated hot gas that is rejected from an air conditioner or heat pump compressor, sitting outside the home, and transfers the heat to the water circulating through the heat exchanger. The active desuperheater water heater works only when the air conditioner or heat pump is operating in a cooling mode.

Another alternative method for heating water is a heat pump water heater. A heat pump water heater contains a fan, compressor, and an evaporator configured to sit on top of the water storage tank. The heat pump water heater circulates a refrigerant through an evaporator and compressor, and uses a fan and evaporator to pull heat from air surrounding the heat pump water heater in order to heat the refrigerant. The heated refrigerant runs through a condenser coil within the water storage tank, transferring heat to the water stored therein.

Yet another alternative method for heating water is a HVAC system coupled with a water heater module to form a multi-purpose system. This multi-purpose system utilizes a water heater module to divert a refrigerant to an indoor unit assembly when conditioning an interior space, or to the water heater module's heat exchanger when heating water. The outdoor heat pump circulates a refrigerant through an evaporator and compressor, and uses a fan and the evaporator to pull heat from air surrounding the heat pump in order to heat the refrigerant. The heated refrigerant runs through the water heater module heat exchanger, transferring heat to water also circulating through the water heater module heat exchanger.

During water heating operation, as the heated water returns to the water storage tank for domestic use, premature mixing of the heated water and the cooler water within the tank may occur. Premature mixing can lower the temperature of the water at the top of the tank which is distributed from the tank for usage, or it can raise the average temperature of the water being pulled from the bottom of the tank for heating, and thus lower the efficiency of the water heating module during the water heating mode. Therefore, there is a need for a method to improve the water heating cycle for optimal performance.

SUMMARY OF THE DISCLOSED EMBODIMENTS

In one aspect, a method for improving a water heater cycle in a multi-purpose HVAC system is provided. In one embodiment, the method includes the step of operating the multi-purpose HVAC system in a water heating mode. In one embodiment, the multi-purpose HVAC system includes an outdoor unit assembly operably coupled to a water heater module, the water heater module including, a controller, at least one valve, a pump, and a temperature sensor. In one embodiment, the multi-purpose HVAC system includes an indoor unit assembly operably coupled to the water heater module. In one embodiment, the at least one valve includes a pair of three way valves. In one embodiment, the multi-purpose HVAC system is configured to circulate a refrigerant from the outdoor unit assembly through the water heater module, and return to the outdoor unit assembly. In one embodiment, operating the multi-purpose HVAC system in a water heating mode generally includes operating the at least one valve to configure a refrigerant circuit. For example, a refrigerant circuit is generally configured by the controller commanding one or more of the at least one valves to be placed in an open state, and commanding one or more of the at least one valves to be placed in a closed state.

The method includes the step of operating the pump at a first rate of speed. In one embodiment, the first rate of speed is less than or equal to four gallons per minute. The method includes the step of determining if a predetermined condition has been satisfied. The method includes the step of operating the pump at a second rate of speed, if the predetermined condition has been satisfied. In one embodiment, the second rate of speed is greater than four gallons per minute. In one embodiment, the pump operates at a second rate of speed when the predetermined condition includes the first water temperature being greater than or equal to a predetermined water temperature. In one embodiment, the predetermined water temperature may be between approximately 100° F. and approximately 120° F. In another embodiment, the pump operates at the second rate of speed after operating the pump at a first rate of speed for a predetermined duration of time.

In one aspect, a multi-purpose HVAC system for heating water and conditioning an interior space is provided. In one embodiment, the multi-purpose HVAC system includes an outdoor unit assembly, an indoor unit assembly, a water heater module including, a heat exchanger, at least one valve, a pump and a temperature sensor, a plurality of conduits fluidically coupling the water heater module to the outdoor unit assembly and the indoor unit assembly, and a controller electrically coupled to the at least one valve, the pump and the temperature sensor wherein the controller is configured to operate the outdoor unit assembly and the water heater module in a water heating mode. In one embodiment, the controller is configured to operate one or more of the at least one valve to configure a refrigerant circuit. In one embodiment, the at least one valve includes a pair of three way valves.

In one embodiment, the at least one valve includes a first valve, a first conduit coupling the first valve to an inlet of the heat exchanger, a second valve, a second conduit coupling the second valve to an outlet of the heat exchanger, a third valve, a third conduit coupling the third valve to the first valve, a fourth valve, a fourth conduit coupling the fourth valve to the second valve, wherein the controller is configured to open the first and second valves and close the third and fourth valves to configure the refrigerant circuit.

In one embodiment, the controller is configured to operate the pump at a first rate of speed. In one embodiment, the first rate of speed is less than or equal to four gallons per minute.

In one embodiment, the controller is configured to determine if a predetermined condition has been satisfied. In one embodiment, the controller is configured to operate the pump at a second rate of speed if the predetermined condition has been satisfied. In one embodiment, the second rate of speed is greater than four gallons per minute.

In one embodiment, the controller is configured to operate the pump at the second rate of speed when operating the temperature sensor to measure a first water temperature and the predetermined condition comprises the first water temperature being greater than or equal to a predetermined water temperature. In one embodiment, the predetermined water temperature may be between approximately 100° F. and approximately 120° F. In another embodiment, the controller is configured to operate the pump at the second rate of speed when predetermined condition includes operating the pump at the first rate of speed for a predetermined duration of time.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments and other features, advantages and disclosures contained herein, and the manner of attaining them, will become apparent and the present disclosure will be better understood by reference to the following description of various exemplary embodiments of the present disclosure taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic diagram of a system for heating water and conditioning an interior space in one embodiment;

FIG. 2 is a schematic flow diagram of a method for improving a water heating cycle in a system for heating water and conditioning an interior space in an exemplary embodiment;

FIG. 3 is a schematic flow diagram of an embodiment of the method for improving a water heating cycle in a system for heating water and conditioning an interior space in an exemplary embodiment; and

FIG. 4 is a schematic flow diagram of another embodiment of the method for improving a water heating cycle in a system for heating water and conditioning an interior space in an exemplary embodiment.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS

For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of this disclosure is thereby intended.

FIG. 1 illustrates a multi-purpose system for heating water and conditioning an interior space, utilizing an embodiment of the present disclosure, and indicated generally at 10. Particularly, the multi-purpose system 10 includes a water heater module 12 operably coupled to an outdoor unit assembly 20 and an indoor unit assembly 22.

Water heater module 12 includes a heat exchanger 16 configured to allow a refrigerant to circulate therethrough. The water heater module 12 includes a plurality of valves 14A-E configured to direct the flow of the refrigerant therethrough. The refrigerant supply side inlet of heat exchanger 16 is coupled to valve 14A via a conduit 24. The refrigerant return side outlet of heat exchanger 16 is coupled to valve 14C via a conduit 26. A valve 14B is coupled to valve 14A via a conduit 28. A valve 14D is coupled to valve 14C via a conduit 30. The valves 14A and 14B are further coupled to an outdoor unit assembly supply connector 32 via a conduit 34. Valve 14B is further coupled to an indoor unit assembly supply connector 36 via a conduit 38. It will be appreciated that the valves 14A and 14B, together with the conduits 28, 34 and 38, function as a first three-way valve. The valves 14C and 14D are further coupled to an outdoor unit assembly return connector 40 via a conduit 42. Valve 14D is further coupled to an indoor unit assembly return connector 44 via a conduit 46. It will be appreciated that the valves 14C and 14D, together with the conduits 30, 42, and 46 function as a second three-way valve. A valve 14E, configured to relieve pressure within the multipurpose HVAC system 10, is coupled to the refrigerant side inlet of the heat exchanger 16 via a conduit 25. Valve 14E is coupled to the indoor unit supply connector 36 via a conduit 27.

Water heater module 12 further includes a water pump 18 to draw water therein. Water pump 18 is configured to operate at least two rates of speed. Water pump 18 is coupled to a water supply connector 31 via a conduit 15. Water pump 18 is further coupled to heat exchanger 16 via a conduit 17. The water heater module 12 includes a water return connector 33, which is coupled to heat exchanger 16 via a conduit 19. The water heater module 12 includes a temperature sensor 21 that is configured to measure the temperature of the water entering through water supply connector 31.

A controller 48 is operably coupled, for example by electrical communication, to each of the plurality of valves 14A-E, the water pump 18, for control thereof. The controller 48 is operably coupled, for example by electrical communication, to the water temperature sensor 21 to receive an input therefrom. The controller 48 provides the water heater module 12 with a variety of operation modes and control sequences to execute instructions during an interior space conditioning mode or water heating mode.

Outdoor unit assembly 20 includes a second heat exchanger 50, a compressor 52, a fan 54, and an expansion device 56. Outdoor unit assemblies 20 include, but are not limited to air-to-air or ground source heat pumps. Expansion device 56 of outdoor unit assembly 20 is fluidically coupled to the outdoor unit assembly return connector 40 via a conduit 58. Outdoor unit assembly 20 is fluidically coupled to the outdoor unit assembly supply connector 32 via a conduit 60.

Indoor unit assembly 22 includes a third heat exchanger 62, an expansion device 64, and an indoor fan 66. Indoor unit assemblies 22 include, but are not limited to air handlers. Indoor unit assembly 22 is fluidically coupled to the indoor unit assembly return connector 44 via a conduit 68 and fluidically coupled to the indoor unit assembly supply connector 36 via a conduit 70.

Water heater module 12 is in electrical communication with outdoor unit assembly 20 and indoor unit assembly 22 via a wired or wireless connection (not shown). Water heater module 12 generally operates to switch the outdoor unit assembly 20 and the indoor unit assembly 22 between an interior space conditioning mode and a water heating mode.

A water storage tank such as the tank 72 is configured to produce a signal to indicate when a water heating mode should be initiated. Water storage tank 72 is fluidically coupled to the water supply connector 31 via a conduit 74 and fluidically coupled to the water return connector 33 via a conduit 76. During a demand to heat water, water storage tank 72 is configured to send a signal to water heater module 12 to operate in a water heating mode.

FIG. 2 illustrates an exemplary method 100 for improving a water heater cycle in a multi-purpose system 10 for heating water and conditioning an interior space. Method 100 includes the step 102 of operating the multi-purpose system 10 in a water heating mode. In one embodiment, the multi-purpose system 10 generally operates in a water heating mode by operating one or more of the at least one valves 14A-D to configure a refrigerant circuit. For example, the refrigerant circuit may be configured by controller 48 commanding valves 14A and 14C to be placed in an open state, and commanding valves 14B and 14D to be placed in a closed state. In one embodiment, outdoor unit assembly 20 is configured to circulate a refrigerant from compressor 52 into conduit 60. The refrigerant generally enters the water heater module 12 through outdoor unit assembly supply connector 32, wherein the refrigerant is directed through valve 14A and circulates through heat exchanger supply conduit 24. The refrigerant generally circulates through heat exchanger 16 and exits heat exchanger 16 via heat exchanger return conduit 26. The refrigerant is generally directed through valve 14C, and exits through outdoor unit assembly return connector 40. The refrigerant generally returns to outdoor unit assembly 20 via conduit 58, through the expansion device 56, and through second heat exchanger 50. The refrigerant will continue to circulate through the refrigerant circuit until the water heating demand is satisfied.

Step 104 includes operating the pump 18 at a first rate of speed. In one embodiment, the first rate of speed may be less than or equal to four gallons per minute. Water is generally drawn into water heater module 12 via water pump 18. Water is generally drawn from water storage tank 72 via conduit 74, wherein it enters water heater module 12 through water supply connector 31 and conduit 15.

Step 106 includes determining if a predetermined condition has been satisfied. . In one embodiment, a first water temperature is measured by the temperature sensor 21 as it enters the water heater module 12 through the water supply connector 31. Water passes through water pump 18 and enters heat exchanger 16 via conduit 17. As heat is transferred from the refrigerant to the water, the water exits heat exchanger 16 via conduit 19. The heated water exits water heater module 12 through water return connector 33 via a conduit 76, wherein the heated water is returned to water storage tank 72.

Step 108 includes operating the pump 18 at a second rate of speed if the predetermined condition has been satisfied. In one embodiment, the second rate of speed may be greater than four gallons per minute. In one embodiment, as shown in FIG. 3, the pump 18 operates at the second rate of speed when the predetermined condition comprises the first water temperature being greater than or equal to a predetermined water temperature. In one embodiment, the predetermined water temperature may be between approximately 100° F. and approximately 120° F. In another embodiment, as shown in FIG. 4, the pump 18 operates at the second rate of speed when predetermined condition comprises operating the pump 18 at the first rate of speed for a predetermined duration of time. For example, pump 18 may operate at the first rate of speed for approximately fifteen minutes prior to operating at the second rate of speed, to name one non-limiting example. As the heated water circulates through the water heater module 12 and gradually mixes with the water within water storage tank 72, the overall temperature of the water supply increases more efficiently. During use, water exits water storage tank 72 via domestic supply line 78, and returns via domestic return line 80.

It will be appreciated that, because water is initially circulated through the water heater module 12 at a lower rate of speed, the likelihood of premature mixing of the heated water and the cooler water within the water storage tank 72 is reduced; thus, enhancing the performance of the water heater module 12.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. 

What is claimed is:
 1. A method for improving a water heating cycle in a multi-purpose HVAC system including an outdoor unit assembly operably coupled to a water heater module, the water heater module including at least one valve, a pump, and a temperature sensor, the multi-purpose HVAC system further including an indoor unit assembly operably coupled to the water heater module, the method comprising the steps of: (a) operating the multi-purpose HVAC system in a water heating mode; (b) operating the pump at a first rate of speed; (c) determining if a predetermined condition has been satisfied; and (d) if the predetermined condition has been satisfied, operating the pump at a second rate of speed.
 2. The method of claim 1, wherein the at least one valve comprises a pair of three way valves.
 3. The method of claim 1, wherein step (a) comprises operating one or more of the at least one valve to configure a refrigerant circuit.
 4. The method of claim 3, wherein: the at least one valve comprises: a first valve coupled to an inlet of a heat exchanger via a first conduit; a second valve coupled to an outlet of the heat exchanger via a second conduit; a third valve coupled to the first valve via a third conduit; a fourth valve coupled to the second valve via a fourth conduit; and step (a) comprises opening the first and second valves and closing the third and fourth valves.
 5. The method of claim 3, wherein the refrigerant circuit circulates a refrigerant from the outdoor unit assembly, through the water heater module, and returns to the outdoor unit assembly.
 6. The method of claim 1, wherein the first rate of speed is less than or equal to four gallons per minute.
 7. The method of claim 1, wherein the second rate of speed is greater than 4 gallons per minute.
 8. The method of claim 1, wherein step (c) further comprises operating the temperature sensor to measure a first water temperature and the predetermined condition comprises the first water temperature being greater than or equal to a predetermined water temperature.
 9. The method of claim 1, wherein the predetermined condition comprises operating the pump at the first rate of speed for a predetermined duration of time.
 10. The method of claim 8, wherein the predetermined water temperature is between approximately 100° F. and approximately 120° F.
 11. A multi-purpose HVAC system comprising an outdoor unit assembly; an indoor unit assembly; a water heater module including at least one valve, a pump, and a temperature sensor; a plurality of conduits operatively coupling the water heater module to the outdoor unit assembly and the indoor unit assembly; and a controller in electrical communication with, the at least one valve, the pump, and the temperature sensor; wherein the controller is configured to: (a) operate the multi-purpose HVAC system in a water heating mode; (b) operate the pump at a first rate of speed; (c) determine if a predetermined condition has been satisfied; and (d) operate the pump at a second rate of speed, if the predetermined condition has been satisfied.
 12. The multi-purpose HVAC system of claim 11, wherein the at least one valve comprises a pair of three way valves.
 13. The multi-purpose HVAC system of claim 11, wherein step (a) comprises the controller operating one or more of the at least one valves to configure a refrigerant circuit to circulate a refrigerant from the outdoor unit assembly through the water heater module, and returns to the outdoor unit assembly.
 14. The multi-purpose HVAC system of claim 13, wherein the at least one valve comprises: a first valve; a first conduit coupling the first valve to an inlet of the heat exchanger; a second valve; a second conduit coupling the second valve to an outlet of the heat exchanger; a third valve; a third conduit coupling the third valve to the first valve; a fourth valve; a fourth conduit coupling the fourth valve to the second valve; wherein the controller is configured to open the first and second valves and close the third and fourth valves to configure the refrigerant circuit.
 15. The multi-purpose HVAC system of claim 11, wherein the first rate of speed is less than or equal to four gallons per minute.
 16. The multi-purpose HVAC system of claim 11, wherein the second rate of speed is greater than 4 gallons per minute.
 17. The multi-purpose HVAC system of claim 11, wherein the controller operates the pump at the second rate of speed when the temperature sensor measures a first water temperature and the predetermined condition comprises the first water temperature being greater than or equal to a predetermined water temperature.
 18. The multi-purpose HVAC system of claim 11, wherein the controller operates the pump at the second rate of speed when predetermined condition comprises operating the pump at the first rate of speed for a predetermined duration of time.
 19. The multi-purpose HVAC system of claim 17, wherein the predetermined water temperature is between approximately 100° F. and approximately 120° F. 